With satellite channels, you can start recording one (manually) and switch to another channel without stopping the recording (because of the dual tuners), but for some reason the 921 does not allow you to start recording an OTA channel then switch away from it to a satellite channel. It forces you to stop the recording before it lets you change channels.

Is there a hardware limitation preventing this? Or could this be changed?

If i remember correctly, the issue with this one is if you have a timer that has a 'manual stop', regardless if its OTA or SAT. Now, all OTA timers set real-time are 'manual end' and that will hopefully change when we start getting OTA guide info. On SAT channels, if you hit the record button, select options, and select manual end, you will get the same problems.

This has been discussed in other threads as well, and most feel as Mark stated above that it is a bug. The question / problem is, you are responsible for going back to your recording to manually stop it. If you don't, then you can easily fill up your DVR.

I think we will see alot less of this once OTA guide info becomes available and we can set instant timers that end at the end of the event. Mark, is it working good on your Beta release?

If I want to record something that I am currently watching OTA, I go to the guide and find a 1/2 hr show in the near future and create a DVR timer.

Then, I go and edit that timer go to the OTA channel and fire a couple minutes later until the expected end time for what I am trying to record.

Of course, by the time I've finished, I've missed about 5 minutes of whatever I am trying to record, but at least I can time/shift, commercial skip whatever I've recorded. It's been helpful for OTA HD Olympic coverage.

Or you could just do Menu-7, select create, enter channel '9999', which takes you to the end of the Sat channels and shows the OTA channels, set the time (can be current or even in the past, it will start the timer as soon as you save it regardless) and there you have it.